Baby bottles are containers for holding liquids, such as infant formula, milk, juice and the like, that allow liquid to flow out of the bottle and into an infant's mouth without spillage of the bottle contents. Such prevention of spillage is accomplished through the use of a rubberized nipple that is placed over the mouth of the bottle, and sealed to the mouth of the bottle by a retaining ring. The rubberized nipple contains a hole, or a plurality of holes, that allows liquid contained in the bottle to pass through the nipple and into a baby's mouth. An internally threaded retaining ring engages an externally threaded mouth portion of the bottle to seal the nipple over the mouth of the bottle. Thus, liquids contained in the bottle flow through the nipple in a restricted fashion, rather than flowing freely through the mouth of the bottle. When in use, the nipple is placed into an infant's mouth, and the contents of the bottle flow through the nipple. When not in use, a threaded cap or stopper can be placed over the mouth of the bottle to protect the contents from spills, evaporation, or contamination from foreign substances.
In most baby bottles sold today, rather than including a stopper or cap along with the retaining ring and nipple, a manufacturer provides a sealing disk that allows a user to seal the contents of the baby bottle with the retaining ring. A sealing disk is a radial disk that is placed between the nipple and the retaining ring to prevent spillage of the bottle's contents. When a baby bottle is not being used to feed an infant, the nipple is inverted, i.e., rotated to face the baby bottle and placed on the mouth of the baby bottle after which the sealing disk is placed on top of the nipple and the retaining ring is secured to the mouth of the bottle thereby securing the nipple and the sealing disk to the mouth of the bottle. When used in this fashion, the sealing disk prevents any liquids contained in the bottle that would otherwise flow through the nipple from escaping from the bottle. The sealing disk has thus provided an inexpensive way to seal a baby bottle without requiring the manufacture to provide both a retaining ring and a stopper or cap.
A problem occurs however when the sealing disk is removed from the bottle so that the bottle can be used to feed an infant. When the sealing disk is removed from the bottle, the nipple is inverted so as to face the infant and the retaining ring is placed over the mouth of the bottle to seal the nipple to the mouth of the bottle. This allows the liquid contained in the bottle to pass through the nipple and to the infant. However, as is often the case, when the bottle is in use, the sealing disk is misplaced, lost or thrown away. With no mechanism remaining to re-seal the bottle, the contents of the bottle spill out through the holes in the nipple when the bottle is not is use.